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Insulation Properties and Degradation Mechanism for XLPE Subjected to Different Aging Periods

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CSEE Journal of Power and Energy Systems 2023年第5期9卷 1959-1967页

作者： Qian Wang Rui Liu Sichen Qin Xi Chen Zicai Shen Zhe Hou Zeli Ju the Department of Electrical engineering Xi’an University of TechnologyXi’an 710048China the Beijing Institute of Spacecraft Environment Engineering Beijing 100094China the State Grid Shaanxi Electric Power Research institute Xi’an 710100China

Due to its excellent insulation and mechanical properties,cross-linked polyethylene(XLPE)is widely used as the insulation candidate of power cables in power transmission and distribution systems.However,its performance can be affected due to various stresses,which endangers safe operation of the power system in service.In this paper,dielectric and insulation properties of XLPE materials of 110 kV cables with the service lives of 0,15,and 30 years were tested and evaluated.Results show that with increase of service life,dielectric loss caused by the polarization process increases significantly,and dielectric strength decreases as well.Power frequency breakdown field strength and crystallinity decrease significantly,and carbonyl index increases.The degradation process of XLPE can be divided into two stages:the structure of the crystalline region of the original sample is relatively complete,and loss can be almost ignored.After long-term service,the crystallization region is destroyed,and thermal oxygen reaction occurs.Intermolecular force is weakened,which makes breakdown easier to occur.However,there is no direct relation between the carbonyl index and macroscopic characteristics.This paper reveals the deterioration law of the XLPE cable insulation,which provides a theoretical basis for evaluating cable aging condition and is of great significance to improve cable operation safety and maintenance quality.

关键词： Crosslinked polyethylene dielectric properties insulation performance microstructure power frequency breakdown

Stable Runge-Kutta discontinuous Galerkin solver for hypersonic rarefied gaseous flow based on 2D Boltzmann kinetic model equations

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Applied Mathematics and Mechanics(English Edition) 2017年第3期38卷 343-362页

作者： Wei SU Zhenyu TANG Bijiao HE Guobiao CAI School of Astronautics Beihang University Beijing 100191 China Beijing Institute of Spacecraft Environment Engineering Beijing 100094 China

A stable high-order Runge-Kutta discontinuous Galerkin(RKDG) scheme that strictly preserves positivity of the solution is designed to solve the Boltzmann kinetic equation with model collision integrals. Stability is kept by accuracy of velocity discretization, conservative calculation of the discrete collision relaxation term, and a limiter. By keeping the time step smaller than the local mean collision time and forcing positivity values of velocity distribution functions on certain points, the limiter can preserve positivity of solutions to the cell average velocity distribution functions. Verification is performed with a normal shock wave at a Mach number 2.05, a hypersonic flow about a two-dimensional(2D) cylinder at Mach numbers 6.0 and 12.0, and an unsteady shock tube flow. The results show that, the scheme is stable and accurate to capture shock structures in steady and unsteady hypersonic rarefied gaseous flows. Compared with two widely used limiters, the current limiter has the advantage of easy implementation and ability of minimizing the influence of accuracy of the original RKDG method.

关键词： model equation hypersonic flow discontinuous Galerkin (DG) conservative discretization positivity-preserving limiter Courant-Friedrichs-Lewy (CFL) condition

Design and Verification of High Attenuation Vibration Isolation Damper in Remote Sensing Satellite Transport

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Journal of Harbin institute of Technology(New Series) 2021年第6期28卷 63-71页

作者： Hao Fu Wei Zhang Junliang Liu Shangjie Pan Beijing Institute of Spacecraft Environment Engineering Beijing 100094China Harbin institute of Technology School of Mechatronics EngineeringHarbin 150001China

To solve the safe horizontal transportation by rail&road of remote sensing satellite problem in the process of unpredictable dynamic load,a high attenuation vibration isolation damper(hereinafter referred to as vibration isolation damper)was developed.By simulation analysis and transportation test using satellite structural model and engineering prototype,validity and reliability of the vibration isolation damper was verified,which can meet the requirements of vibration and shock from various transportation conditions.

关键词： satellite structural model high attenuation vibration isolation damper dynamic analysis

On the source of the quasi-Carrington Rotation periodic magnetic variations on the Martian surface: InSight observations and modeling

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Earth and Planetary Physics 2022年第3期6卷 275-283页

作者： Hao Luo AiMin Du ShaoHua Zhang YaSong Ge Ying Zhang ShuQuan Sun Lin Zhao Lin Tian SongYan Li Key Laboratory of Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China College of Earth Science University of Chinese Academy of SciencesBeijing 100049China Beijing Institute of Spacecraft Environment Engineering Beijing 100094China

In a recent paper(Luo H et al.,2022),we found that the peak amplitudes of diurnal magnetic variations,measured during martian days(sols)at the InSight landing site,exhibited quasi Carrington-Rotation(qCR)periods at higher eigenmodes of the natural orthogonal components(NOC);these results were based on~664 sols of magnetic field measurements.However,the source of these periodic variations is still unknown.In this paper we introduce the neutral-wind driven ionospheric dynamo current model(e.g.,Lillis et al.,2019)to investigate the source.Four candidates-the draped IMF,electron density/plasma density,the neutral densities,and the electron temperature in the ionosphere with artificial qCR periodicity,are applied in the modeling to find the main factor likely to be causing the observed surface magnetic field variations that exhibit the same qCR periods.Results show that the electron density/plasma density,which controls the total conductivity in the dynamo region,appears to account for the greatest part of the surface qCR variations;its contribution reaches about 67.6%.The draped IMF,the neutral densities,and the electron temperature account,respectively,for only about 12.9%,10.3%,and 9.2%of the variations.Our study implies that the qCR magnetic variations on the Martian surface are due primarily to variations of the dynamo currents caused by the electron density variations.We suggest also that the timevarying fields with the qCR period could be used to probe the Martian interior's electrical conductivity structure to a depth of at least 700 km.

关键词： InSight sol magnetic variations Carrington Rotation(CR)periodicity

Research on Assembly Technology of Complex Flexible Out-cabin Motional Cable for spacecraft

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Research on Assembly Technology of Complex Flexible Out-cabi...

Synchronization for Complex Networks with Randomly Occurring Coupling Delays via Passivity

作者： Chunsheng Yang Yi Lu Yu Wang Feng Xue Zhenyue Ren Beijing Institute of Spacecraft Environment Engineering

Based on the application of flexible cable assembly simulation analysis technology in complex flexible out-cabin motional cable assembly of spacecraft, the working environment and physical characteristics of flexible motional cable are analyzed, reasonable assembly constraints are planned, and cable assembly simulation analysis is described in detail. The research results not only ensure the accuracy and practicability of the design, but also reduce the assembly defects and product failure rate. The actual effect of cable assembly can be accurately judged, the product performance can be improved, the product development cycle can be saved, and the development cost can be significantly reduced.

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Synchronization for Complex Networks with Randomly Occurring...

Ultralong Stretchable Soft Actuator(US2A):Design,Modeling and Application

第30届中国控制与决策会议

作者： Dongliang Wu Zhenwei Li Tao Liao Jing Wang Beijing Institute of Spacecraft Environment Engineering

This paper deals with the synchronization problem for complex networks under the passivity framework.In particular,the randomly occurring coupling delays are taken into account to describe more complicated dynamics in the real world.By means of stochastic analysis,delay-dependent sufficient synchronization criteria can be given for ensuring the desired passivity performance by matrix techniques.With the established conditions being satisfied,the designing procedure for the synchronization controller is proposed.Finally,we give an illustrative example for illustrating the efficiency of our synchronization strategy.

关键词： Synchronization Complex networks Randomly occurring coupling delays Passivity

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Chinese Journal of Mechanical engineering 2023年第1期36卷 280-291页

作者： Wenbiao Wang Yunfei Zhu Shibo Cai Guanjun Bao Key Laboratory of Special Purpose Equipment and Advanced Processing Technology Ministry of EducationZhejiang University of TechnologyHangzhou310014China Beijing Institute of Spacecraft Environment Engineering China Academy of Space TechnologyBeijing100094China

Actuator plays a significant role in soft robotics.This paper proposed an ultralong stretchable soft actuator(US2A)with a variable and sizeable maximum elongation.The US2A is composed of a silicone rubber tube and a bellows woven sleeve.The maximal extension can be conveniently regulated by just adjusting the wrinkles’initial angle of the bellows woven sleeve.The kinematics of US2A could be obtained by geometrically analyzing the structure of the bellows woven sleeve when the silicone rubber tube is inflated.Based on the principle of virtual work,the actuating models have been established:the pressure-elongation model and the pressure-force model.These models reflect the influence of the silicone tube’s shell thickness and material properties on the pneumatic muscle’s performance,which facilitates the optimal design of US2A for various working conditions.The experimental results showed that the maximum elongation of the US2A prototype is 257%,and the effective elongation could be variably regulated in the range of 0 and 257%.The proposed models were also verified by pressure-elongation and pressure-force experiments,with an average error of 5%and 2.5%,respectively.Finally,based on the US2A,we designed a pneumatic rehabilitation glove,soft arm robot,and rigid-soft coupling continuous robot,which further verified the feasibility of US2A as a soft driving component.

关键词： Soft robotics Soft actuator Pneumatic artificial muscle Modeling

Co-design of Event-triggered and Passive-based Filter for Networked Markov Jump Systems

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Co-design of Event-triggered and Passive-based Filter for Ne...

Analysis and control optimization of positive pressure fluctuation in electromechanical oxygen regulator

第36届中国控制会议

作者： Peng Guo Dongliang Wu Wanqing An Bin Shen Beijing Institute of Spacecraft Environment Engineering

ISBN: (纸本)9781538629185

This paper deals with the filter design problem for the networked Markov jump systems. In particular, a co-design of event-triggered and passive-based filtering scheme is developed. Based on the designed event-triggering mechanism, passivity performance is investigated for the derived filtering error system. By using the Lyapunov-Krasovskii functional, sufficient conditions are established to ensure that the filtering error system can achieve the prescribed passivity index. Then, the modedependent filter gains and the event-triggered parameters can be co-designed in terms of linear matrix inequalities（LMIs）.Finally, simulation results are presented to validate our theoretical results.

关键词： Event-triggered filter Passive-based filter Markov jump systems

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Chinese Journal of Aeronautics 2021年第5期34卷 205-213页

作者： Rui PAN Guiping LIN Zhigao SHI Yu ZENG Xue YANG School of Aeronautic Science and engineering Beihang UniversityBeijing 100083China Hefei Jianghang Aircraft Equipment Corporation Ltd AVICHefei 230051China Beijing Institute of Spacecraft Environment Engineering Beijing 100094China

The Electromechanical Oxygen Regulator(EMOR)is a new type of aviator oxygen equipment.Positive pressure refers to the pressure difference between the breath pressure and the ambient pressure during pressurized oxygen supply.The phenomenon of positive pressure fluctuation was believed to reduce the system performance.The current open-loop control method cannot solve this problem.In this paper,the mathematical model was established and main factors were analyzed.By combining experimental research and simulation calculation,it was determined that pressure fluctuation was caused by inlet pressure and diaphragm deformation together.With the increase of pulmonary ventilation volume,the influence of inlet pressure on fluctuation decreases gradually,while the proportion of diaphragm deformation increases rapidly.A closed-loop control strategy of Proportional Resonant with Feedforward Compensation(PRFC)was proposed to solve the problem and control parameters were obtained through co-simulation.The effectiveness of the control strategy was verified by experiments.The results show that the control strategy can enhance the anti-disturbance ability of the system and significantly reduce the pressure fluctuation range,which is beneficial to improving the overall system performance.

关键词： Aviator oxygen system Electromechanical Oxygen Regulator(EMOR) Feedforward control Disturbance rejection Proportional resonant control